A forensic standard procedure is described that combines enzyme-linked immunoassay for screening and gas chromatography-mass spectrometry (GC-MS) for confirmation to detect drugs of abuse in a sample before used to detect opioids and cocaine. We used two equal aliquots of the same previously selected cannabinoid positive hair samples, one of which was subjected to acid hydrolysis. Afterward, both the aliquots were subjected to basic extraction and then to immunoassay screening. After derivatization, the GC-MS parameters were the same for both the aliquots for the determination of the cannabinoids (Δ(9)-tetrahydrocannabinol, cannabidiol and cannabinol). The results show that there were no statistical differences between the nonpreviously treated and the pretreated hair samples for the quantification of the three cannabis products for immunochemical procedure. No differences between the two groups were shown as for GC-MS confirmation procedures. All substances showed a good linearity between 0.05 and 2 ng/mg. The limit of detection ranged from 0.02 to 0.03 ng/mg, and the limit of quantification was 0.05 ng/mg for all substances. To our knowledge, this is the first time that screening and confirmation procedures have been applied on the same sample of hair to detect more than one drug of abuse.

The purpose of this study was to develop and validate a gas chromatography-mass spectrometry method to detect drugs of abuse in a single sample of tooth. Pulverized samples of dental materials were subjected to acid hydrolysis to detect opiates, cocaine and their metabolites. The residual dental materials from these analyses were subjected to basic extraction to detect cannabis products (Δ-tetrahydrocannabinol, cannabidiol and cannabinol). The method showed a good linearity between 0.05 and 2 ng/mg for all substances. The limit of detection ranged from 0.02 to 0.03 ng/mg, and the limit of quantification was 0.05 ng/mg. The application of the method to samples of teeth obtained from drug addicts was successful. It can be applied in post-mortem cases, especially when limited amounts of sample are available.

In this case study, the body of a 45-year-old man was exhumed after 1 year at the request of the public prosecutor to assess whether the death was caused by drug consumption. Toxicological analyses were performed on several matrices, including liver, kidney, and the alternative matrices hair and teeth. The systematic toxicological analysis (STA), which consisted of basic and acid liquid/liquid extraction and gas chromatography-mass spectrometry (GC-MS) analysis, showed the presence of opiates in each of the matrices analyzed. Subsequently, to confirm and quantify the presence of opioids, samples of each of the matrices were subjected to solid-phase extraction and specific GC-MS analysis. The case presented demonstrates the possibility of drug detection in an exhumed body that has been buried for 1 year, despite the problems of quantitative interpretation of the data, and that toxicological results could be useful along with other forensic evidence.

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